1. Field of the Invention
The present invention relates to support elements, and more particularly concerns support elements for interior areas that are difficult to access.
2. Description of Related Art
Assemblies of various types incorporating multiple elements confined within a space that has limited or difficult access may experience undesired motion, accelerations and vibration in response to shock, acceleration and vibration to which the overall device may be subjected. Such external forces can cause damage to the parts or to the overall system unless parts, which are otherwise loosely held to one another in a particular position, are firmly stabilized. A traveling wave tube is but one example of a system having a number of internal parts which must be firmly positioned and stabilized against external shock, acceleration and vibration. One such type of traveling wave tube, an elongated coupled cavity traveling wave tube, incorporates an elongated coupled cavity circuit, coupled at opposite ends to input and output RF ports, and surrounding a tube through which an electron beam is projected from an electron gun at one end of the tube to a collector at the other end. To focus the electron beam within the electron beam tube, a plurality of annular magnetic coils (twelve, in one system), termed a solenoid, are arranged in an elongated stack surrounding the coupled cavity circuit and effectively extend from one RF port to the other. The entire system is mounted in an exterior device housing that is sealed around the input and output RF ports by means of input and output port sealing rings that surround some of the magnetic coils. Spaces between adjacent ones of the magnetic coils are partly filled by insertion of stabilizing elements to stabilize coil positions. However, the intercoil space at the position of each of the sealing rings is not accessible to positioning of a stabilizing element after assembly of the coils. The sealing rings prevent the application of hot melt plastic to spaces in these positions.
In prior coupled cavity traveling wave tubes these inaccessible intercoil spaces have been merely left as dead, unoccupied spaces. Alternatively, solid or resilient elements have been positioned in these spaces prior to the stacking of the annular coils on the coupled cavity circuit. When the stacking has been completed in such an arrangement, and before the stabilizing elements are inserted, the coils are relatively loose in the axial direction with respect to one another, defining intercoil spaces that are then filled with stabilizing elements, such as, for example, by injection of hot melt plastic. However, since at least one or generally two of the intercoil spaces, namely those to which access is prevented by the presence of the sealing rings, cannot be filled with the stabilizing element after assembly of the stack, the cumulative effect of varying position and relative axial motion of one coil with respect to another effectively results in an inability to firmly stabilize position and longitudinal motion of the coils. Tube operation may be degraded by vibration or other movement of the coils and tube life is limited by vibration induced wear on the coils. Accordingly, prior coupled cavity traveling wave tubes have exhibited increased and undesirable sensitivity to external shock and vibration that degrades performance and decreases tube life.
It is an object of the present invention to avoid or minimize above mentioned problems.